Hi Neil! The real question you need to answer is "for the printed wiring
assemblies I plan to process, do have a large enough process window or do I
need to use an inert atmosphere (eg. N2) to increase the size of the
process window"?  Many Pbfree soldering processes will be perfectly
adequate with air atmospheres in their process but folks with large pwas or
heavy thermal demand pwas will use N2 to improve the soldering process. But
that larger process window comes at a price - N2 isn't free.  Inert
atmospheres are a choice, not a necessity. Good Luck.

Dave Hillman
Rockwell Collins
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             Neil Maloney
             <nmaloney@CCONTRO
             LS.COM>                                                    To
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             <[log in to unmask]>                                          cc

                                                                   Subject
             01/18/2006 02:31          [TN] Time to fish or cut bait
             PM


             Please respond to
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             ; Please respond
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               Neil Maloney
             <nmaloney@CCONTRO
                  LS.COM>






Greetings, Technet!

My company is making the transition from leaded to lead -free assembly
in the US (we have already converted our overseas facility) Now we are
in the throes of the N2 vs. air battle.   Our overseas unit uses air
only without any problems  (ENIG boards, 0602s to QFPs, no BGAs)   In
the US we are looking to start designing  BGA and flip-chip assemblies
with the same type ENIG and Entek boards.  We are buying a new 10 zone
reflow oven, and battle begins. Do we start with nitrogen or not? Can a
small company make lead-free BGA assemblies without going to an N2
atmosphere?

Does air make the process window too small for BGA?

Our smallest PCB is about 8x12cm.


Thanks in advance


Neil Maloney, Manufacturing Engineer
Contemporary Control Systems, inc
2431 Curtiss St Downers Grove, IL  60515
(630) 963-7070 x132
[log in to unmask]
http://www.ccontrols.com <http://www.ccontrols.com/>
http://www.ctrlink.com <http://www.ctrlink.com/>



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